Treatment apparatus with a heater adhesively joined to a bandage

ABSTRACT

A wound treatment apparatus is provided which includes a thermally conductive bandage, a heater in contact with the bandage over a wound treatment area, and an adhesive attachment device for maintaining thermally conductive contact between the heater and the bandage. The bandage and heater together have a low profile so as to be convenient for the patient and are flexible so as to conform to the shape of the wound and to the contours of the skin surrounding the wound. The attachment device is fashioned so as to have less pull strength than an adhesive holding the bandage to the person&#39;s body so that the heater can be easily removed without disturbing the attachment of the bandage to the person&#39;s body. The bandage is provided with a polymeric film for maintaining moisture at the wound site as well as enhancing the utility of the attachment device.

CROSS-REFERENCES TO RELATED PATENT AND COPENDING APPLICATIONS

[0001] This application contains material related to U.S. patentapplication Ser. No. 08/843,072 filed on Apr. 11, 1997 entitled“FLEXIBLE NON-CONTACT WOUND TREATMENT DEVICE WITH A SINGLE JOINT” and tothe following commonly assigned pending U.S. patent applications:

[0002] Ser. No. 07/900,656, filed Jun. 19, 1992, for “THERMAL BODYTREATMENT APPARATUS AND METHOD”;

[0003] Ser. No. 08/342,741, filed Nov. 21, 1994, for “WOUND TREATMENTDEVICE”;

[0004] Ser. No. 08/356,325, filed Feb. 21, 1995, for “WOUND COVERING”;

[0005] Ser. No. 08/785,794, filed Jan. 21, 1997, for “NORMOTHERMICHEATER WOUND COVERING”;

[0006] Ser. No. 08/786,713, filed Jan. 21, 1997, for “NORMOTHERMICTISSUE HEATING WOUND COVERING”;

[0007] Ser. No. 08/786,714, filed Jan. 21, 1997, for “NEAR HYPOTHERMICHEATER WOUND COVERING”; and

[0008] Ser. No. 08/838,618, filed Apr. 11, 1997, for “FLEXIBLENON-CONTACT WOUND TREATMENT DEVICE”.

[0009] This application also contains material related to the followingcommonly assigned U.S. Patent Applications, which were concurrentlyfiled with this application:

[0010] Ser. No. ______ filed ______ for “WOUND TREATMENT APPARATUS WITHHEAT SPREADING DEVICE”;

[0011] Ser. No. ______ filed ______ for “WOUND TREATMENT APPARATUS WITHINFRARED ABSORPTIVE WOUND COVER”;

[0012] Ser. No. _______ filed ______ for “WOUND TREATMENT APPARATUS WITHIR-TRANSPARENT OR IR-TRANSMISSIVE WOUND COVER”; and

[0013] Ser. No. ______ filed _______ for “WOUND TREATMENT APPARATUS FORNORMOTHERMIC TREATMENT OF WOUNDS”.

STATEMENT OF REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0014] Not Applicable

REFERENCE TO A MICROFICHE APPENDIX

[0015] Not Applicable

BACKGROUND OF THE INVENTION

[0016] 1. Field of the Invention

[0017] The present invention relates to a wound treatment device with abandage and heater that are essentially planar, yet flexible, and areconnected or joined by an attachment device that promotes heat transferfrom the heater to the bandage and permits removal of the heater fromthe bandage while the bandage remains on the patient.

[0018] 2. Description of the Related Art

[0019] Wounds, in general, are breaks in the integrity of the skin of apatient. A first type of wound may result from mechanical trauma thatproduces a cut, tear, or an abrasion. There are many instruments ofcausality for such wounds, including knives. glass, gravel, or ascalpel. A second type of wound may be caused by a combination of heatand pressure wherein the heat alone is insufficient to cause an outrightburn. Such wounds include pressure sores, decubitus ulcers, or bedsores, and reflect an injury that is chronic in nature. A wound may alsobe vascular in origin. In this third type of wound, blood flow through aregion may be altered sufficiently to cause secondary weakening oftissues which are eventually disrupted, thus forming a wound. In thecase of arterial causes, the primary difficulty is getting oxygenatedblood to the affected area. For venous causes, the primary difficulty isfluid congestion in the affected area which backs up, decreasing theflow of oxygenated blood. Because these wounds manifest underlyingchronic disease processes, such as atherosclerotic vascular disease,congestive heart failure, and diabetes, these vascular injuries also arechronic in nature, forming wounds with ulcerated bases.

[0020] Heat therapy has been used to treat wounds since the days ofHippocrates, with varying results. Up to now, heat therapy for woundshas involved the application of heat under conditions that make thetissues of a wound hyperthermic. Hyperthermia impedes wound healing andmay actually damage the wound tissues.

[0021] The “normal” range of temperature for the human body is in therange of 37° C.±1° C. (36° C.-38° C.). This is termed the “normothermic”range. Humans exhibit a thermoregulatory response to core temperaturechanges as little as ±0.1° C., wherein “core” as used herein refers tointerior portions of the body. This extremely tight temperature controlis necessary because virtually all cellular functions, chemicalreactions and enzymatic reactions are optimum at normothermia.

[0022] Surface tissue varies in temperature according to whereon thebody it is located. The skin of the torso is usually hypothermic, whilethe skin of the legs is always hypothermic. The normal skin temperatureof the distal leg is approximately 32° C., which is considered to be“moderately hypothermic”. The skin temperature of the distal leg of apatient with vascular insufficiency may be as low as 25° C., which is“severely hypothermic”. The hypothermic condition of wounds and ulcersinhibits healing. Severely hypothermic skin or wound tissue is in astate that may be termed “suspended animation”. In suspended animation.tissue is living, but cellular functions necessary for cell division andcollagen deposition are slowed or even stopped. Further, the immunesystem is inhibited, allowing wounds to become heavily colonized withbacteria. The local application of heat to hypothermic skin will causesome degree of vasodilatation, resulting in an increase in local bloodflow. Increased blood flow increases the subcutaneous oxygen tension(PsqO₂) which, in turn, increases both collagen deposition and immunefunction.

[0023] Many references report that the immune system is inhibited byhypothermia and activated by mild hyperthermia (fever). Persp BiolMed:439-474. Spring 1980, reports that local body temperature is acritical factor determining host susceptibility, the location of lesionsand contracting infectious diseases. New Eng J Med 305:808-814, 1981,reports that animals exposed to cold environments are more susceptibleto infectious diseases, whereas exposure to high ambient temperaturesoften produces a beneficial result. Wound Rep Reg 2:48-56, 1994 and ActaAnaesth Scand 38:201-205, 1994, report that infections caused by astandard inoculum of e. coli or s. aureus were significantly more severein hypothermic guinea pigs than in normothermic control animals. New EngJ Med 334:1209-1215, 1996, reports that hypothermic colorectal surgicalpatients had three times more wound infections (19% vs. 6%) than thosewho were kept normothermic during surgery with a Bair Hugger® patientwarming system described in commonly assigned U.S. Pat. Nos. 5,324,320,5,300,102 and 5,350,417. Further, six weeks of warming therapy with theBair Hugger® patient warming system has successfully healed chronicprogressive ulcers which heretofore have been resistant to standardtherapies.

[0024] Currently available medical devices that apply heat to woundsinclude infrared lights, warm water pads, warm water bottles, whirlpoolsand Sitz baths. All types of lesions, such as surgical, chronic,traumatic, donor sites, infected wounds and burns, have been treatedwith these warming modalities. Particularly difficult has been theapplication of heat to open wounds such as ulcers. Treatment of a woundwith infrared light requires that the wound be positioned under thelight during therapy, necessitating patient immobility. Further, theinfrared heat causes the wound to dry, thereby slowing the healingprocess. Warm water pads and bottles and electrical heating pads arecumbersome, reduce patient mobility, and are usually applied to theextremities and held in place with inconvenient wraps such as straps,hook-and-eye material or tabs. Whirlpools and Sitz baths reduce mobilityand limit the duration of warming therapy due to skin maceration by thewater. None of these modalities is capable of prolonged heat treatmentof a wound.

SUMMARY OF THE INVENTION

[0025] There is a need for a wound treatment apparatus to convenientlytreat a wound with heat therapy for a prolonged period of time, whileallowing patient mobility. It is also important that the wound treatmentapparatus be flexible and have a low profile for convenience of thepatient. Such a wound treatment apparatus should be thermally conductivefor efficient heat transfer, be convenient to operate without adverselyimpacting the patient, and be capable of maintaining a moist woundenvironment.

[0026] Preferably, the operation of the wound treatment apparatus isreferred to a “wound treatment area” (or “treatment area”) that mayinclude the wound, unwounded skin adjacent the wound (the periwound), orboth.

[0027] In order to deliver heat therapy to a wound treatment area itwould be beneficial to employ standard bandages that are available forwound treatment. In this case, a heater may conveniently be placed ontop of such a bandage and the heater/bandage apparatus may be placed onthe wound treatment area. The heater and bandage are joined by anadhesive attachment device.

[0028] The bandage should preferably just cover the treatment area.Attachment of the bandage to a person's body then becomes an importantvariable if the heater must be removed while the bandage remains inplace. That is, removal of the heater should not disturb the attachmentof the bandage to the person's body. This requires consideration ofattachment devices that act between the heater and the bandage andbetween the bandage and the person's body.

[0029] The bandage is preferably thermally conductive. Thermallyconductive bandages may be made of such materials as hydrogels,hydrocolloids, moist gauze, moist foam, hydrated alginates and polymericfilms. In a preferred embodiment, an upper surface of the bandageincludes a layer of moisture-impermeable material. With thisarrangement, the bandage protects and maintains the humidity of thewound bed and the adjacent tissue.

[0030] The heater may be fashioned to primarily heat the wound, toprimarily heat the periwound area, or to heat both the wound and theperiwound area. Exemplary heat sources are electrical resistanceheaters, chemical heaters, water pad heaters and phase-change saltheaters. In one embodiment of the invention, electrical resistanceelements are embedded in or laminated to a flexible film, such assilicon, flexible rubber or flexible cloth. With this arrangement theheater is planar and flexible with a low profile. Alternatively, a waterpad heater can be used. Such a heater may be made by thermo-forming twosheets of polymeric film into fluid channels and sealing the periphery.Warm water is then circulated through the pad by an external heater andpump. In other embodiments, a chemical heater or a phase-change saltheater may be used.

[0031] The attachment device may be made of a layer of polymeric filmwith a layer of adhesive applied to both sides which is commonlyreferred as “two-faced tape” or “double-sided tape”. In anotherembodiment, a layer of adhesive is applied to a surface of the bandageand/or the heater. The attachment device may be continuous across theentire treatment area so that uniform bonding will promote uniformconductive heat transfer from the heater to the bandage. The attachmentdevice employs an adhesive in contrast to straps, hook-and-eye materialor tabs. These latter devices allow air spaces to develop between theheater and the bandage resulting in poor and unpredictable heat transferto the wound.

[0032] In a preferred embodiment, the heater is detachable from thebandage when it is not in use. In one embodiment, this may beaccomplished by making the adhesive between the heater and the bandageless tacky than the adhesive between the bandage and the skin.Alternatively, the adhesive applied to the double-sided tape, or toeither or both of the surfaces of the heater and the bandage, can bearranged in an intermittent pattern so that its pull strength is lessthan the pull strength of the adhesive holding the bandage to the skinsurface. In embodiments where the adhesive is applied to the surface ofeach of the heater and the bandage, the adhesive may be selected from agroup of adhesives that are not tacky to the touch but will adhere toeach other.

[0033] An object of the present invention is to provide an apparatus fortreating wounds with heat which has a low profile for convenience of apatient, is flexible for mobility of the patient and transfers heat byconduction to a wound and/or periwound site so as to promote heattreatment thereof.

[0034] Another object is to provide a substantially planar woundtreatment apparatus that conforms to the wound and the adjacent skin.

[0035] A further object is to provide a low profile and flexible woundtreatment apparatus that provides heat transfer to a wound and is easyto operate without impacting the patient's comfort.

[0036] Still another object is to provide a low profile, flexible woundtreatment apparatus that includes a heater attached to a bandage whereinthe heater can be easily detached from the bandage without detaching thebandage from the skin of a patient.

[0037] Still a further object is to provide a highly mobile andconvenient wound treatment apparatus which promotes heat transfer to awound and which maintains a moist environment thereon.

[0038] Other objects and advantages of the invention will becomeapparent upon reading the following description taken together with theaccompanying drawings.

DESCRIPTION OF THE DRAWINGS

[0039]FIG. 1 is an isometric view of a first embodiment of the woundtreatment apparatus being applied to a wound on a person's body;

[0040]FIG. 2 is an isometric view of the wound treatment apparatusapplied to the wound on the person's body;

[0041]FIG. 3 is an exploded isometric view of the wound treatmentapparatus;

[0042]FIG. 4 is a cross-sectional view of the wound treatment apparatusapplied to the wound on the person's body;

[0043]FIG. 5 is an exploded cross-sectional illustration of anembodiment of the invention above the wound area of the person's body;

[0044]FIG. 6 is a view taken along plane VI-VI of FIG. 5;

[0045]FIG. 7 is a view taken along plane VII-VII of FIG. 5;

[0046]FIG. 8 is a view taken along plane VIII-VIII of FIG. 5;

[0047]FIG. 9 is a view taken along plane IX-IX of FIG. 5;

[0048]FIG. 10 is a view taken along plane X-X of FIG. 5;

[0049]FIG. 11 is a view taken along plane XI-XI of FIG. 5;

[0050]FIG. 12 is a view taken along plane XII-XII of FIG. 5;

[0051]FIG. 13 is an exploded cross-sectional view of the firstembodiment of the wound treatment apparatus after attaching anattachment device to the heater;

[0052]FIG. 14A is a planar illustration of an electrical resistanceelement embedded in a flexible layer for uniform heating;

[0053]FIG. 14B is a view taken along plane XIVB-XIVB of FIG. 14A;

[0054]FIG. 15A is a planar view of an electrical resistance elementembedded in a flexible layer for heating a portion of a treatment area;

[0055]FIG. 15B is a view taken along plane XVB-XVB of FIG. 15A;

[0056]FIG. 16A is a planar view of an electrical resistance elementembedded in a flexible layer for uniform heating of a central portion ofa treatment area;

[0057]FIG. 16B is a view taken along plane XVIB-XVIB of FIG. 16A;

[0058]FIG. 17 is an exploded cross-sectional view of another embodimentof the invention shown above a wound area;

[0059]FIG. 18 is a view taken along plane XVIII-XVIII of FIG. 17;

[0060]FIG. 19 is a view taken along plane XIX-XIX of FIG. 17;

[0061]FIG. 20 is a view taken along plane XX-XX of FIG. 17;

[0062]FIG. 21 is a view taken along plane XXI-XXI of FIG. 17;

[0063]FIG. 22 is a view taken along plane XXII-XXII of FIG. 17;

[0064]FIG. 23 is a view taken along plane XXIII-XXIII of FIG. 17;

[0065]FIG. 24 is a view taken along plane XXIV-XXIV of FIG. 17;

[0066]FIG. 25 is a view taken along plane XXV-XXV of FIG. 17;

[0067]FIG. 26 is a view taken along plane XXVI-XXVI of FIG. 17;

[0068]FIG. 27 is a view taken along plane XXVII-XXVII of FIG. 17;

[0069]FIG. 28 is a view showing schematically the engagement of theintermittent adhesives shown in FIGS. 26 and 27;

[0070]FIG. 29 is an isometric illustration of a further embodiment ofthe wound treatment apparatus applied to a wound on the person's body;

[0071]FIG. 30 is an exploded cross-sectional illustration of theapparatus shown in FIG. 29 shown above the wound;

[0072]FIG. 31 is an exploded cross-sectional illustration of the FIG. 29embodiment with an adhesive attachment device applied to the heater;

[0073]FIG. 32 is an isometric illustration of a still another embodimentof the invention applied to a wound on the person's body;

[0074]FIG. 33 is an exploded cross-sectional illustration of the FIG. 32embodiment shown above the wound; and

[0075]FIG. 34 is an exploded cross-sectional illustration of the FIG. 32embodiment with an adhesive attachment device applied to the heater.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0076] Referring now to FIGS. 1-34, wherein like reference numeralsdesignate like or similar parts throughout the several views there areshown various embodiments of a wound treatment apparatus in according tothe invention.

[0077] As shown in FIGS. 1-6, one embodiment of the wound treatmentapparatus 100 includes a thermally conductive bandage 102 which hasfirst (lower) and second (upper) surfaces 104 and 106, a heater 108which has first (lower) and second (upper) surfaces 110 and 112 and anattachment device 114 for joining the heater 108 and the bandage 102 insuch a manner as to transfer heat from the heater 108 to the bandage102. Preferably, the attachment device maintains surface-to-surfacecontact between the second surface 106 of the bandage 102 and the firstsurface 110 of the heater. In FIGS. 2 and 4, the wound treatmentapparatus 100 is shown in place covering a wound 116 of a person's body118, the wound being shown depressed. Immediately adjacent the wound isa periwound area 120 which is typically a peripheral band of tissuearound the wound area with less trauma than the tissue of the woundarea. As will be explained in more detail hereinafter, the woundtreatment apparatus is capable of treating a wound treatment area thatincludes the wound and/or the periwound area. as desired.

[0078] The second surface 106 of the bandage preferably comprises asheet of smooth material. In a preferred embodiment, this surface may beprovided by a polymeric film. A layer 122 of hydrogel, hydrocolloid, orhydrated alginate may be affixed to the polymeric film 106 by anysuitable means, such as an adhesive, and may provide the first surface104. It is preferred that any of these combinations provide the bandagewith high thermal conductivity and maintain a moist environment at thewound. In the layer 122, a foam or gauze may be used in lieu of thecompounds enumerated above. If the gauze or foam provides the firstsurface 104, the gauze or foam will absorb moisture from the wound,providing the desired heat conductivity and moist environment.Alternatively, the bandage 102 may simply be a single layer or film of aheat-conductive polymer so as to optimize heat conductivity of thebandage. In any embodiment of the bandage, it is preferred that thebandage be planar, as shown in FIGS. 3 and 5, and be flexible to conformto the wound 116 as shown in FIG. 4, as well as the person's body, asshown in FIGS. 1 and 2.

[0079] In the embodiment 100 of the wound treatment apparatus, theheater 108 includes means for generating heat that may be electricallyoperated. For example, the means may take the form of an electricalresistance element 124 which is embedded in or laminated to a flexibleplanar member 126, such as polyethylene, silicon, rubber or flexiblecloth. In the preferred embodiment, the heater 108 is substantiallyplanar, as shown in FIGS. 1, 3 and 5, and yet flexible in order that itconform, with the bandage, to the wound 116, as shown in FIG. 4, and tothe person's body as shown in FIGS. 2 and 4. As will be explained inmore detail hereinafter, the adhesive attachment device 114 joins theheater 108 to the bandage 102, as shown in FIG. 4, so as to maximizeheat transfer between the heater 108 and the bandage 102.

[0080] As illustrated in FIGS. 1 and 4, the electrical resistanceelement 124 is connected to first and second electrical conductors 128and 130, which are connected to an electrical power source 132, via acontroller 134. The purpose of the controller 134 is to controlelectrical power provided to the electrical resistance element 124 tomaintain a normothermic temperature at or near the wound 116. As shownin FIGS. 1 and 2, the electrical resistance element 124 may extend backand forth in the flexible planar member 126 with a desired spacing topromote uniform heating of the heater 108.

[0081] As shown in FIG. 6, the first surface 104 of the bandage 102 isprovided with an open pattern of adhesive 136 at or near its periphery.The adhesive pattern 136 may completely encompass the wound and theperiwound area so as to trap the natural moisture of the body which, inturn, moistens the layer 122 of the bandage, or otherwise maintains amoist environment across the wound treatment area for wound therapypurposes. Accordingly, the pattern of adhesive 136 has inner and outerboundaries 138 and 140 wherein, in the preferred embodiment, the outerboundary 140 coincides with the outer perimeter of the bandage. Itshould be understood that the bandage 102, the heater 108, and thepattern of adhesive 136 may take various shapes, such as the square,shown in the drawings, or a rectangle, circle or ellipse, or any otherregular or irregular shape. depending upon various shapes of woundtreatment areas.

[0082] The preferred adhesive attachment device 114 is a double-sidedtape, as shown in FIG. 5. It is preferred that the double-sided tape bea polymeric film with first and second surfaces with first and secondlayers of adhesive 142 and 144 thereon. The double-sided tape comes withfirst and second release liners 146 and 148 which are removed so thatthe adhesive layers 142 and 144 can be joined to the second surface 106of the bandage 102 and to the first surface 110 of the heater 108,respectively, as shown in FIGS. 1, 4 and 5. In FIG. 1, the release liner146 is partially removed from the adhesive layer 142 (see FIG. 5) inpreparation for attaching the heater 108 to the second surface 106 ofthe bandage 102. The double-sided tape 114 is very flexible and conductsheat between the heater 108 and the bandage 102. It is preferred thatthe planar dimensions of the double-sided tape 114 be the same as theplanar dimension of the heater 108 so as to transfer heat from theentire first surface 110 of the heater 108 to the bandage 102. It shouldbe noted that, because of the polymeric film 106 forming the secondsurface of the bandage 102, transfer of heat by conduction to thebandage 102 is promoted.

[0083] When heat therapy is interrupted or terminated, it may bedesirable to detach the heater 108 from the bandage 102. In this regard,the heater 108 is preferably detachably joined to the bandage 102.Detachment in the embodiment just described will necessitate pulling theheater 108 away from the bandage 102, thereby subjecting each adhesivelayer therebelow to a pull force. In order for the bandage 102 to remainin place while the heater 108 is being removed, the pull strength of theattachment device 114 must be less than the pull strength of the patternof adhesive 136. Various means for achieving this objective withdouble-sided tape are shown in FIGS. 7-12. FIGS. 7 and 8 show theadhesive layers 142 and 144 completely covering the surfaces of thepolymeric film. One of these surfaces will be required to have less pullstrength than the pull strength of the pattern of adhesive 136. In apreferred embodiment, the adhesive layer 142 has less pull strength thaneach of the pattern of adhesive 136 and the adhesive layer 144, allowingthe heater 108 to be removed from the bandage 102 without leaving anyadhesive on the bandage. This may be accomplished by employing anadhesive layer 142 which is less tacky than each of the pattern ofadhesive 136 and the adhesive layer 144. Less tack can be achieved bydoping the same adhesive with a solvent or inert filler, such as talcumor chalk, or employing another adhesive with a tack known to be lessthan the tack of the adhesives 136 and 144. If it is desired to leavethe adhesive on the bandage 102, then the roles of the tack would beswitched between the adhesive layers 142 and 144.

[0084] Lower pull strength of the adhesive between the heater 108 andthe bandage 102, as compared to the pull strength of the adhesiveattaching the bandage 102 to a person's body, can be provided byintermittent adhesive patterns such as the circular regions 142 i shownin FIG. 9. In contrast, as shown in FIG. 10, the adhesive layer 144would be an entire plane so that when the heater is pulled, thedouble-sided tape leaves with the heater 108 rather than being retainedon the bandage 102. As shown in FIG. 9, the adhesive regions 142 i maybe numerous circular dots of adhesive which are sized and spaced fromone another in a matrix to provide a pull strength of the adhesiveattachment device that is less than the pull strength of the pattern ofadhesive 136 and less than continuous adhesive layer 144. With thisarrangement, the same adhesive may be used for the adhesive layers 142and 144 of the double-sided tape and the pattern of adhesive 136 on thebandage. Again, the layers 142 and 144 of the double-sided tape 114 maybe switched if it is desired to leave the double-sided tape on thebandage 102 when the heater 108 is pulled therefrom. Anotherintermittent adhesive pattern is shown at 142 s in FIG. 11, whereindiagonal spaced-apart strips of adhesive material are provided acrossthe polymeric film. Here again, the sizing of the strips and theirspacing from one another are arranged so that the pull strength of theadhesive attachment device is less than the pull strength of each of thepattern of adhesive 136 and the full plane adhesive layer 144 in FIG.12. It should be understood that the intermittent adhesive structure maytake various patterns in order to achieve the desired reduction in pullstrength. The spacing between the intermittent layers should be made assmall as possible so as to promote conductive heat transfer between theheater 108 and the bandage 102.

[0085] In FIG. 13 the adhesive layer 142 of the double-sided tape hasbeen applied to the first surface 110 of the heater 108 and the releaseliner 146 has been partially removed from the first adhesive layer 142,similar to the showing in FIG. 1. The heater 108 may be supplied withthe double-sided tape in place, as shown in FIG. 13, or may be suppliedseparately as described and shown in FIG. 5.

[0086] Manifestly, an attachment device should permit the heater andbandage to be joined in such a way as to maximize heat transfertherebetween while permitting the heater to be detached from the bandagewithout detaching the bandage from the skin. While various adhesiveconfigurations are shown for this purpose, it is contemplated that otherattachment mechanisms could be used.

[0087] FIGS. 14-16 illustrate various embodiments of electricalresistance heaters 108. Any of these embodiments are intended to be usedin the embodiment of FIGS. 1 and 2. In the heater 108 a shown in FIG.14A, and electrical resistance element 124 a winds back and forth withinthe flexible planar member 126, similar to what is shown in FIG. 1. Thespacing between the windings of the electrical resistance element 124 amay be sized so as to ensure substantially uniform heating. FIG. 14Bshows the electrical resistance element embedded or laminated in theflexible planar member 126. In FIG. 15A, the electrical resistanceelement 124 b takes a path along a peripheral zone of the flexibleplanar member 126, so that the periphery of the heater 108 b isuniformly heated to a temperature greater than a central portion of theheater. Again, these electrical resistance elements 124 b are shownembedded or laminated in the flexible planar member 126 in FIG. 15B. InFIG. 16A, the electrical resistance element 124 c takes a spiral pathout and back within a central region of the heater 108 c so as touniformly heat the central region of the heater to a higher temperaturethan regions outbound therefrom. The heater 108 a is adapted forapplying heat to both the wound and periwound area 116 and 120 in FIG.4, the heater 108 b is adapted for applying heat primarily to theperiwound area 120 and the heater 108 c is adapted for applying heatprimarily to the wound 116.

[0088] Another embodiment 200 of the wound treatment apparatus isillustrated in FIG. 17, wherein an adhesive layer 202 is on the secondsurface 106 of the bandage 102 and/or an adhesive layer 204 is on thefirst surface 110 of the heater 108. Various embodiments of theseattachment devices are illustrated in FIGS. 18-28. Various heaterembodiments are illustrated in FIGS. 14A through 16B. The firstembodiment of the attachment device is shown in FIGS. 18 and 19, whereinthe heater 108 is provided with the adhesive layer 204 and the bandage102 is not provided with any adhesive layer. In FIGS. 20 and 21, thesituation is reversed wherein the bandage 102 is provided with theadhesive layer 202 and the heater 108 does not have an adhesive layer.FIGS. 22 and 23 illustrate a still further embodiment wherein thebandage 102 is provided with the adhesive layer 202 and the heater 108is provided with the adhesive layer 204. The adhesive layers 202 and 204in FIGS. 22 and 23 may be made from an adhesive which will bond onlywhen these two adhesive layers are placed in contact with one another.Otherwise, the adhesive layer 204 will not bond to the polymeric surfacesurrounding the adhesive layer 202, or any other surface including aperson's skin. This scheme has an advantage from the standpoint thatadhesive layers 202 and 204 on the bandage 102 and the heater 108,respectively, will not attach to anything until they are brought intocontact between the heater 108 and the bandage 102. This promotesmanufacturability, logistics and operation of the invention. A suitableadhesive for this purpose is 3 M Non-Tacky Adhesive SJ-3101. It isdesirable that the pull strength of the adhesive attachment devicesshown in FIGS. 18-23 be lower than the pull strength of the bodyadhesive 136 shown in FIG. 6. This can be accomplished by making thetack of the adhesive attachment device less than the tack of the patternadhesive 136.

[0089] Attachment devices employing intermittent adhesive patterns areshown in FIGS. 24-28. The embodiment in FIGS. 24 and 25 shows the heater108 provided with circular spaced-apart adhesive regions 204 c, whilethe bandage 102 is not provided with any adhesive. In the embodimentshown in FIGS. 26 and 27, each of the bandage 102 and the heater 108 isprovided with diagonal spaced-apart adhesive strips 202 d and 204 d,respectively. When these adhesive strips are brought into contact withone another, as shown in FIG. 28, they criss-cross one another toprovide the desired bonding between the heater 108 and the bandage 102.

[0090] The adhesive areas of the intermittent adhesive patterns shown inFIGS. 24-28 are sized and spaced from one another so that the pullstrength of each attachment device is less than the pull strength of thepattern adhesive 136 shown in FIG. 6, as discussed hereinabove. Again,the size of the intermittent adhesive patterns and the spacingtherebetween should be tailored to maximize thermal conductivity betweenthe heater 108 and the bandage 102 and yet ensure that the pull strengthbetween the heater and the bandage is less than the pull strengthbetween the bandage and the person's body.

[0091] Another embodiment 300 of the wound treatment apparatus isillustrated in FIGS. 29-31. In this embodiment, a heater 302 employsheated water as the means for generating heat to be provided to thebandage 102. The heater 302 may comprise a pouch 304 which has waterchannels extending back and forth in series from an inlet end 308 to anoutlet end 310. The pouch 304 may be made by thermo-setting theperiphery as well as channel lines of a pair of polymeric films 312 and314 as shown in FIG. 30. The bottom film 314 may be stiffer than the topfilm 312. Heated water is supplied by inlet and outlet water lines 316and 318 which are connected to a water heater 320 via a pump 322. Acontroller 324 is provided for controlling the temperature of the waterin the water heater 320 and the amount of water pumped by the pump 322The heated water is preferably maintained at such a temperature and flowrate that the wound site 116 is maintained at or near a normothermictemperature. The bandage 102 may comprise any of the aforementionedembodiments. Further, the attachment device for attaching the heater 302to the bandage 102 may comprise any of the aforementioned adhesiveattachment devices. or any equivalent devices or arrangements thatconnect the heater and bandage for maximum thermal conductivity, yetallow detachment of the heater from the bandage without detaching thebandage from a patient's skin. The preferred attachment device is thedouble-sided tape 114 shown in FIG. 30, which has been described indetail hereinabove. Another suitable attachment device is shown in FIG.31 wherein the water heater 302 is provided with an adhesive layer 326and a release liner 328. The release liner 328 is simply pulled from theadhesive layer 326 and the adhesive layer 326 is employed for attachingthe water heater 302 to the polymeric surface 106 of the bandage 102.

[0092] Still another embodiment 400 of the wound treatment apparatus isillustrated in FIGS. 32-34. In this embodiment a heater 402 employs achemical or phase-change salt as the means for generating heat to beprovided to the bandage 102. As with the embodiments discussed above,these materials are selected to enable the heater 402 to maintain thewound site 116 at or near a normothermic temperature. As shown in FIG.33, the heater 402 may comprise a pair of polymeric films 404 and 406which are sealed at their peripheries to provide an enclosure for thechemical or phase change salt. Further, the polymeric films 404 and 406may be joined by spot thermosetting at spaced-apart locations 408 forthe purpose of lowering the profile of the heater and maintaining thechemical or phase-change salt in discrete confined areas. The film 406may be stiffer than the film 404. Again, the bandage 102 and theattachment device for attaching the heater 402 to the bandage 102 may beany of the embodiments described hereinabove. The preferred attachmentdevice is the double-sided tape 114, as shown in FIG. 33, which is fillydescribed hereinabove. Alternatively, the heater 402 may be providedwith an adhesive layer 410 which is covered by a release liner 412, asshown in FIG. 34.

[0093] The invention provides a wound treatment device having a lowprofile for the convenience of the patient and permitting easy removalof the heater from a bandage without disturbing the attachment of thebandage to the person's body. The bandage, the heater and the attachmentdevice are all flexible and cooperate to conform to the wound to thecontour of a person's body where the wound is located so as to permit asubstantially hermetic seal about, and moist environment at, the woundsite. Numerous attachment embodiments have been described for making thepull strength between the heater 108 and the bandage 102 less than thepull strength between the bandage 102 and the person's body. Even thoughthe bandage 102 is removable, it is desirable to first remove the heaterand then to take special care in removing the bandage from the person'sbody. The invention also enables treatment of the wound and/or theperiwound, as desired.

[0094] The heater embodiments all enable a wound treatment deviceaccording to this invention to maintain the temperature of a wound siteat or near a normothermic level. That is to say, the wound treatmentdevice maintains the temperature of tissue in and/or near a wound in arange of about 36° C. to about 38° C.

[0095] Clearly, other embodiments and modifications of this inventionwill occur readily to those of ordinary skill in the art in view ofthese teachings. Therefore, this invention is to be limited only by thefollowing claims, which include all such embodiments and modificationswhen viewed in conjunction with the above specification and accompanyingdrawings.

We claim
 1. A wound treatment apparatus comprising: a bandage havingfirst and second surfaces, the first surface of the bandage defining awound treatment area corresponding to a wound site on a person's skin; aheater for maintaining a temperature at the wound treatment area; theheater being in contact with the second surface of the bandage over thewound treatment area; and an adhesive attachment means acting betweenthe heater and the second surface for retaining the heater on thebandage.
 2. The wound treatment apparatus as claimed in claim 1 furtherincluding the bandage being thermally conductive.
 3. The wound treatmentapparatus as claimed in claim 2 wherein each of the heater and thebandage is flexible, such that the heater and the second surface aresubstantially planar when the heater and bandage are nonflexed.
 4. Thewound treatment apparatus as claimed in claim 2 wherein the secondsurface of the bandage comprises a flexible polymeric film.
 5. The woundtreatment apparatus as claimed in claim 4 wherein the bandage includes alayer of a material selected from the group of materials includinggauze, hydrogel, and hydrocolloids and the polymeric film is attached tothe layer.
 6. The wound treatment apparatus as claimed in claim 2including: the bandage including inner and outer boundaries; the innerboundary defining the wound treatment area; and, a pattern of adhesivelocated on the first surface of the bandage between the inner and outerboundaries.
 7. The wound treatment apparatus as claimed in claim 6wherein the bandage includes an outer perimeter and the outer boundarysubstantially approximates the outer perimeter of the bandage.
 8. Thewound treatment apparatus as claimed in claim 6 including: theattachment means including an adhesive device acting between the heaterand the second surface; each of the adhesive device and the pattern ofadhesive having a pull strength; and the pull strength of the adhesivedevice being less than the pull strength of the pattern of adhesive. 9.The wound treatment apparatus as claimed in claim 8 wherein the adhesivedevice includes: a plurality of adhesive regions; and the adhesiveregions being sized and spaced from one another so that the pullstrength of the adhesive device is less than the pull strength of thepattern of adhesive.
 10. The wound treatment apparatus as claimed inclaim 8 including: the adhesive device comprising at least one adhesivelayer with a tack and the pattern of adhesive having a tack; and thetack of the at least one adhesive layer of the adhesive device beingless than the tack of the pattern of adhesive.
 11. The wound treatmentapparatus as claimed in claim 8 wherein the adhesive device includes anadhesive layer that is continuous across the treatment area.
 12. Thewound treatment apparatus as claimed in claim 8 wherein the adhesivedevice includes an adhesive layer that is intermittent across thetreatment area.
 13. The wound treatment apparatus as claimed in claim 8wherein the adhesive device is an adhesive layer or on the heater or thesecond surface of the bandage.
 14. The wound treatment apparatus asclaimed in claim 13 including: the adhesive device including first andsecond adhesive layers; and the first adhesive layer being on the heaterand the second adhesive layer being on the second surface of thebandage.
 15. The wound treatment apparatus as claimed in claim 14wherein the first and second adhesive layers bond when contacting oneanother.
 16. The wound treatment apparatus as claimed in claim 14wherein second surface of the bandage comprises a flexible polymericfilm.
 17. The wound treatment apparatus as claimed in claim 16 whereinthe first and second adhesive layers bond to one another.
 18. The woundtreatment apparatus as claimed in claim 8 wherein the adhesive device isa double-sided tape.
 19. The wound treatment apparatus as claimed inclaim 18 wherein the double-sided tape includes: a flexible polymericfilm that has first and second surfaces; and first and second adhesivelayers, the first adhesive layer being on the first surface of thepolymeric film and the second adhesive layer being on the second surfaceof the polymeric film.
 20. The wound treatment apparatus as claimed inclaim 2 wherein the heater includes means for applying heat acrosssubstantially the entire wound treatment area.
 21. The wound treatmentapparatus as claimed in claim 2 wherein the heater includes means forapplying heat across at least a portion of the wound treatment area. 22.The wound treatment apparatus as claimed in claim 2 wherein the heaterincludes: a pouch; and means for generating heat located within thepouch.
 23. The wound treatment apparatus as claimed in claim 22 whereinthe means for generating heat includes water.
 24. The wound treatmentapparatus as claimed in claim 22 wherein the means for generating heatincludes a chemically reactive material.
 25. The wound treatmentapparatus as claimed in claim 22 wherein the means for generating heatincludes a phase-change salt.
 26. The wound treatment apparatus asclaimed in claim 2 wherein the heater includes an electrical resistanceelement.
 27. The wound treatment apparatus as claimed in claim 26wherein the electrical resistance element is disposed in the heater forgenerating heat across at least a portion of the heater.
 28. The woundtreatment apparatus as claimed in claim 27 wherein the electricalresistance element is located for generating heat in a region of theheater.
 29. The wound treatment apparatus as claimed in claim 26 whereinthe electrical resistance element is positioned for generating heat inonly a portion of the heater.
 30. The wound treatment apparatus asclaimed in claim 29 wherein the electrical resistance element is locatedfor generating heat only in a peripheral region of the heater.
 31. Thewound treatment apparatus as claimed in claim 26 wherein the heaterincludes: a flexible layer; and the electrical resistance element beingembedded in the flexible layer.
 32. The wound treatment apparatus asclaimed in claim 31 wherein the flexible layer is a polymer.
 33. Thewound treatment apparatus as claimed in claim 2 including: inner andouter boundaries on the first surface of the bandage, the inner boundarydefining the wound treatment area; a pattern of adhesive located betweenthe inner and outer boundaries; and the attachment means including anadhesive device having at least one adhesive layer that substantiallyfills the wound treatment area.
 34. The wound treatment apparatus asclaimed in claim 33 including: each of the adhesive device and thepattern of adhesive having a pull strength; and the pull strength of theadhesive device being less than the pull strength of the pattern ofadhesive.
 35. The wound treatment apparatus as claimed in claim 34wherein the heater applies heat across substantially the entire woundtreatment area.
 36. The wound treatment apparatus as claimed in claim 35wherein each of the heater and the bandage is flexible with the heater,the second surface being substantially planar in a nonflexed state. 37.The wound treatment apparatus as claimed in claim 36 wherein the secondsurface of the bandage comprises a flexible polymeric film.
 38. Thewound treatment apparatus as claimed in claim 37 wherein the heaterincludes: a pouch; and means for generating heat located within thepouch.
 39. The wound treatment apparatus as claimed in claim 37 whereinthe heater includes: a flexible layer; and an electrical resistanceelement being embedded in the flexible layer.
 40. The wound treatmentapparatus as claimed in claim 39 wherein the adhesive device includes: aflexible polymeric film that has first and second surfaces; and firstand second adhesive layers, the first adhesive layer being on the firstsurface of the polymeric film and the second adhesive layer being on thesecond surface of the polymeric film.
 41. The wound treatment apparatusas claimed in claim 37 wherein the adhesive device includes: a pluralityof adhesive regions; and the adhesive regions being sized and spacedfrom one another so that the pull strength of the adhesive device isless than the pull strength of the pattern of adhesive.
 42. The woundtreatment apparatus as claimed in claim 37 including: the adhesivedevice comprising at least one adhesive layer with a tack, and thepattern of adhesive; and the tack of the at least one adhesive layer ofthe adhesive device being less than the tack of the adhesive.
 43. Thewound treatment apparatus as claimed in claim 37 wherein the adhesivedevice is an adhesive layer on one of the heater and the second surfaceof the bandage.
 44. The wound treatment apparatus as claimed in claim 43including: the adhesive device including first and second adhesivelayers; and the first adhesive layer being on the first surface of theheater and the second adhesive layer being on the second surface of thebandage.
 45. The wound treatment apparatus as claimed in claim 43wherein the first and second adhesive layers bond only when contactingone another.
 46. The wound treatment apparatus as claimed in claim 43wherein the first and second adhesive layers will bond to one anotherbut will not bond to the polymeric film surface of the bandage.
 47. Thewound treatment apparatus as claimed in claim 43 wherein the adhesivedevice is a double-sided tape.
 48. The wound treatment apparatus asclaimed in claim 47 wherein the double-sided tape includes: a flexiblepolymeric film that has first and second surfaces; and first and secondadhesive layers, the first adhesive layer being on the first surface ofthe polymeric film and the second adhesive layer being on the secondsurface of the polymeric film.
 49. The wound treatment apparatus asclaimed in claim 1 wherein the controller includes means for cycling thetemperature of the heater.
 50. A wound treatment apparatus comprising: abandage having first and second surfaces, the first surface of thebandage defining a treatment area; a heater having first and secondsurfaces; the first surface of the heater being in contact with thesecond surface of the bandage over the treatment area; each of thebandage and the heater being flexible; an adhesive device acting betweenthe first surface of the heater and the second surface of the bandagefor maintaining the contact while permitting the bandage and the heaterto be flexed together; the adhesive device including at least oneadhesive layer that corresponds to the treatment area; a pattern ofadhesive located on the first surface of the bandage; each of theadhesive device and the pattern of adhesive having a pull strength; andthe pull strength of the adhesive device being less than the pullstrength of the pattern of adhesive.
 51. The wound treatment apparatusas claimed in claim 50 wherein the adhesive device includes: a pluralityof adhesive regions; and the adhesive regions being sized and spacedfrom one another so that the pull strength of the adhesive device isless than the pull strength of the pattern of adhesive.
 52. The woundtreatment apparatus as claimed in claim 51 wherein the heater includesan electrical resistance element.
 53. The wound treatment apparatus asclaimed in claim 52 wherein the electrical resistance element is locatedfor providing heat to a central region of the treatment area.
 54. Thewound treatment apparatus as claimed in claim 52 wherein the electricalresistance element is located for providing heat to a peripheral regionof the treatment area.
 55. The wound treatment apparatus as claimed inclaim 50 including: the adhesive device comprising a first adhesivelayer with a tack and the pattern of adhesive having a tack; and thetack of the at least one adhesive layer of the adhesive device beingless than the tack of the pattern of adhesive.
 56. The wound treatmentapparatus as claimed in claim 55 wherein the heater includes anelectrical resistance element.
 57. The wound treatment apparatus asclaimed in claim 56 wherein the electrical resistance element is locatedfor generating heat to in central region of the heater.
 58. The woundtreatment apparatus as claimed in claim 56 wherein the electricalresistance element is located for generating heat in a peripheral regionof the heater.
 59. The wound treatment apparatus as claimed in claim 50including: the adhesive device being first and second adhesive layers;and the first adhesive layer being on the first surface of the heaterand the second adhesive layer being on the second surface of thebandage.
 60. The wound treatment apparatus as claimed in claim 59wherein the first and second adhesive layers bond only when contactingone another.
 61. The wound treatment apparatus as claimed in claim 59wherein the first and second adhesive layers bond to one another. 62.The wound treatment apparatus as claimed in claim 50 wherein theadhesive device is a double-sided tape.
 63. The wound treatmentapparatus as claimed in claim 62 wherein the double-sided tape includes:a flexible polymeric film that has first and second surfaces; and firstand second adhesive layers, the first adhesive layer being on the firstsurface of the polymeric film and the second adhesive layer being on thesecond surface of the polymeric film.
 64. The wound treatment apparatusas claimed in claim 50 wherein the heater includes: a flexible layer;and an electrical resistance element embedded in the flexible layer. 65.The wound treatment apparatus as claimed in claim 64 wherein theelectrical resistance element is for providing heat across substantiallythe entire heater.
 66. The wound treatment apparatus as claimed in claim65 wherein the adhesive device includes: a flexible polymeric film thathas first and second surfaces; and first and second adhesive layers, thefirst adhesive layer being on the first surface of the polymeric filmand the second adhesive layer being on the second surface of thepolymeric film.
 67. The wound treatment apparatus of claim 50, furtherincluding a controller connected to the heater for controlling theheater's temperature.